Holdings of the EMDB by 3DEM technique. A representative example of each category is shown: single particle, human αβ-crystallin 24-mer (EMD-1894, PDB 2YGD); icosahedral, cytoplasmic polyhedrosis virus (EMD-5256, PDB 3IZX); helical, GMPPCP-stabilized human dynamin 1 ΔPRD polymer (EMD-1949, PDB 3ZYS); tomogram or subtomogram average, radial spokes from Chlamydomonas reinhardtii flagella (EMD-1941); 2D crystal, pig gastric H+,K+-ATPase with bound BeF and SCH28080 (EMD-1831, PDB 2XZB)24.